Several Israeli government websites crashed on Sunday in what appeared to be a cyber-attack by hackers. The websites of the IDF, Mossad and the Shin Bet security services were among the sites that went down, as well as several government portals and ministries.

The apparent attack comes after the international cabal of hackers known as Anonymous threatened a cyber-attack on the Israeli government’s computers in response to its interception of a Gaza-bound flotilla on Friday.

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The IDF and Shin Bet said they were investigating the reason for the malfunction. Security officials stressed that only the external government sites crashed, and that the internal computer networks were unharmed.

In a video that was uploaded to YouTube, Anonymous warns that if the siege on Gaza is maintained, it will have no choice but to go on the attack.

Anonymous said that if the siege continues and Israeli forces intercept additional flotillas, or if they conduct additional operations such as the commandeering of the Mavi Marmara, it will have no alternative but to launch repeated cyber-attacks on Israeli computer systems until the siege ends.

Anonymous has succeeded in the past in bringing about the temporary disabling of many websites, including credit card companies that refused to transfer donations to the WikiLeaks organization.

Several months ago, Anonymous announced that they have the code for Stuxnet, which was distributed on the internet. Security experts usually do not see them as a strategic threat, as they do programmers who are responsible for this type of malicious software.

Anonymous threatened to disable the Knesset website a few months ago, but even if hacking did occur then, the website continued to function and did not suffer any apparent damage.

Last May, Israel established a national taskforce to prevent cyber "terror attacks" by foreign countries on its strategic computer networks. The national cybernetic taskforce was set up in order to protect Israel from possible harm to its defense systems and infrastructure networks.

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